The present invention relates generally to electrical connectors and, more particularly, to a contact protection system for electrical connectors.
Electrical connectors are frequently provided with keying means to permit particular pairs of connectors to properly mate and to prevent the mating of connectors which are not intended to be mated. Keying means are especially useful when a plurality of identical connectors are positioned in close proximity to one another, for example, on a printed circuit board. The incorrect matching of complementary connectors to the connectors on the board can cause serious damage to the circuits improperly connected thereby; and the keying means, by insuring that each complementary connector will mate with only the correct one of the plurality of connectors on the board, minimizes the risk of improper connection. Keying means are particularly important when the connections are made by untrained personnel as the risk of improper connection is especially great in such circumstances.
Commonly assigned U.S. patent application Ser. No. 07/090,294 filed on Aug. 31, 1987, discloses a pair of complementary electrical connectors which are adapted to be mated to complete electrical circuits through the connectors. The connectors are of the high density type and include a receptacle connector which is adapted to be mounted to a printed circuit board, and a complementary plug connector which is adapted to terminate an electrical cable. The connectors also include a keying system comprising a pair of keys extending from the mating face of each connector. Each key is secured in its connector in a selected angular orientation with respect to an opposing key on the other connector so that when the connectors are intended to be mated, extended keying sections on the keys pass by each other during mating to allow the connectors to properly mate. If one of the keys is secured in an incorrect orientation with respect to its opposing key, however, the extended keying sections on the keys will abut one another during mating to prevent proper mating of the connectors.
The keying system incorporated in the connectors disclosed in U.S. application Ser. No. 07/090,294 is quite effective in applications in which it is desired to insure that a connector will mate with only the correct one of a plurality of complementary connectors. In other applications, however, the keying system is not required; and the connectors are designed to be readily usable in such applications as well. In particular, each key in the keying system comprises a separate component and is mounted to its respective connector by being supported in a passageway which extends into the connector from the mating face thereof. To use the connectors without the keying system, the keys are simply omitted from the connectors.
When the connectors disclosed in U.S. application Ser. No. 07/090,294 are used without the keys mounted thereon, however, it has been found that substantial care must be exercised during mating of the connectors. In particular, the receptacle connector mounted on the printed circuit board includes a number of features which project upwardly from the mating face thereof. These features include latching features for use in latching the connectors together after mating, and features used to retain the keys in the connector in a selected angular orientation and to provide the connector with a further keying capability. Unless care is exercised during the mating process, the pin contacts on the cable terminating plug connector can pass over and impinge against one or more of the projecting features on the receptacle connector as the connectors are being aligned for mating, and be bent or otherwise damaged thereby.